Documenting the extreme

By using a small mirror with low mass and a control unit capable of turning the mirror at the exact speed at the right moment, FMV is able to film flying projectiles at close distance using high-speed cameras.

To be able to document extreme abilities takes extreme methods. The FMV test range in Karlsborg has the leading experts when it comes to camera based measurements in extreme environments. With, among other equipment, high-speed cameras and x-ray photography it is documented how grenades are penetrating material – processes lasting only a few millionth of a second.

The high-speed cameras are capable of about 700 000 exposures per second and with the use of x-ray flash equipment we are able to see what happens to the material trough fire, smoke and dust when the projectile hit its target. This according to Torben Gustavsson, who works with camera based measurements at the Karlsborg Test Range.

High velocity

One example is a customer who wants to know if their grenade is moving in the right way in the trajectory. Since the grenades velocity is about 1000 metres per second it is not possible to track it with a camera.

To track a missile or grenade at a large distance is usually not a problem with a remote controlled camera rig, but since we have to film at close distance it’s not physically possible to move the camera fast enough to follow the grenade, according to Torben Gustavsson.

There were solutions to the problem available on the market, but at the FMV range in Karlsborg the choice was to develop their own system with better performance than the commercially available systems.

Own system

In this way we got not only better functionality but also a system that is tailor made to our and our customers needs, according to Torben Gustavsson.

By using a small mirror, with low enough mass, to follow the grenade trajectory and a control unit capable of turning the mirror at the exact moment, FMV now have the capability to record flying projectiles at close distance using high-speed cameras.

“It gives us a vast documentation for picture analysis and several spectacular photographs. People are astounded when they see the results. Even if you have worked with grenades for several years few people have seen how a grenade looks when fired in this way.” You learn a lot from this kind of photographs, says Torben Gustavsson.